1. Field of the Invention
The present invention relates to a metalized film capacitor obtained by winding or stacking metalized films, and method of manufacturing the same, and, more particularly, to a surface-mounting metalized film capacitor which can be surface-mounted on a printed circuit board.
2. Description of the Related Art
In recent years, more compact electronic components incorporated in circuits are produced with remarkable increases in packing densities of electronic circuits in the field of electronics. In particular, strong demand has arisen for compact large-capacitance capacitors which can be surface-mounted on printed circuit boards. A typical conventional compact large-capacitance capacitor is a metalized film capacitor. When a surface-mounting metalized film capacitor is generally manufactured, resin films are metalized, and the metalized films are insulated from each other while being wound or stacked. Electrodes are then mounted on the wound or stacked structure.
Published Unexamined Japanese Patent Application No. 59-143,314 discloses a technique for providing a surface-mounting metalized film capacitor. In this prior art, a capacitor element having an outer cover is stored in a case, and lead wires are connected thereto. For this reason, the capacitor becomes bulky, resulting in inconvenience.
Published Unexamined Utility Model Application No. 60-37,235 discloses another technique for providing a surface-mounting metalized film capacitor. In this prior art, each electrode cap is mounted on an internal electrode extraction portion. In this case, since the metalized film capacitor element itself has a low moisture resistance, a resin must be coated on the element by vacuum impregnation or dipping. When the resin is coated on the element by vacuum impregnation or dipping, an insulating layer is formed on the surface of the element electrodes. When the electrodes are soldered during surface-mounting, soldering cannot be performed. Even if soldering of the electrodes can be achieved, high reliability of the soldered portions cannot be guaranteed. In addition, a high-precision metal cap accurately fitted on the outer surface of the element is required, thus degrading productivity.
Published Unexamined Japanese Patent Application No. 61-27,223 describes still another technique for providing a surface-mounting metalized film capacitor. In this prior art, after an external electrode plate is mounted on a capacitor, the resultant structure is molded with a resin. In this prior art, however, since the external electrode plate is employed, the capacitor product is undesirably bulky. In addition, a special lead frame is required, and other components such as a mold for molding the element with a resin are also required. For this reason, the manufacturing steps are complicated as compared with the case wherein the lead wires are extracted.